Q. Why are faint T lines appearing on urine pregnancy tests, while ultrasounds say I am not pregnant?

Hi doctor,

I have been trying to conceive for a few months, but every time the test comes back negative. My last periods was on the 25th of last month, and I started ovulating on the third of this month, and it ended on the 12th. My husband and I had sex on the fifth. Despite my history of irregular periods, I was expecting them to come this time around the same date as I was put on Cabergoline to control my high prolactin (22 on the last report) for regularity of periods. I did not get periods on 25th, but I did not worry too much, as I could have been late in general. However, I checked pregnancy on 20th of this month, which was negative, but I kept the kit. I checked the pregnancy again on 28th and found it negative again, and kept the kit again.

After a few hours, I went back to throw the kits, and I found a very faint line on the 28th one, and checked the other one also and found a very faint line on that also. The one on 20th was more fade than the one on 28th. I thought it is urine or evaporation line, and did not take it seriously. I went to the hospital, and the doctors did not find any gestational sac or ectopic pregnancy in ultrasounds also. Nothing at all. But as I had a faint line, they asked me to come back after 10 days.

Yesterday morning, I again did a home pregnancy test. Within 2 to 3 minutes, I got another faint T line. This time it was a bit darker as compared to the previous one. I do not understand what is going on. The doctors said that there is nothing called as false positive if the test is checked within prescribed time frame, and a T line appears only when there is some hCG hormone, however, nothing on the ultrasounds.

My all four I-can strips show faint lines, but the Prega news kit does not show anything at all. Complete negative. My ultrasound shows nothing. What could be happening with me? My medications since last month are Cabergoline, Metformin, and Folic acid. The doctors say that it could be too early to say something, or it could be ectopic, which could not be verified in the ultrasounds. Could you please give me some opinion on this, as to what could have been the reasons for faint T line appearing within 2 to 3 minutes, while ultrasounds say I am not pregnant?